The defense can get by on what they have, especially when some injured/suspended players return. Maybe add a safety that would at least be a minor upgrade on what they have.
What they absolutely HAVE to do is add a #1 WR that changes the ENTIRE offense. I don't care how many draft picks they need to give away, or how you need to manipulate the cap, do it already. This team only succeeds when Allen can do his thing, and getting a true #1 changes everything for Josh, Shakir, Coleman, Kincaid, and Cook.